Many integrated circuits contain important data which have to be kept secret, for examples codes which are used for encryption, identification and/or authentication purposes. These integrated circuits (chips) are used, for example, in banking applications, ticketing applications or pay TV applications.
Chips which are used in these fields have to be security-certified. Basically, a security certification of this kind proves that the integrated circuit meets a certain security standard. In order to meet a security standard it is usually required that the integrated circuit is sufficiently resistant against tampering. In other words, the integrated circuit must be resistant against all kinds of attacks which aim at retrieval of codes or uncontrolled change of functionality of said integrated circuit.
One important form of attack consists of reverse engineering of the integrated circuit. Another possible attack is to modify the integrated circuit in such a way that certain security measures, for example electrical shields, are circumvented. This kind of attacks typically requires physical or chemical modification of the chip, for example the removal of passivation layers. Unfortunately, such attacks typically go unnoticed because conventional integrated circuits are not capable of detecting removal of a passivation layer autonomously.